^9^ On the 'EleBridty excited hy the 



they will have attained the fame force as that of the 20t1t 



arc 



If the twenty arcs in the middle were all turned in xht 

 fame dire6lion as the preceding twenty and the following 

 twenty, that is to fay, if the whole 60 confpired to impel the 

 tleclric fluid in the fame direftion, it may readily be com- 

 prehended how much greater the effeft will be at the end^ 

 and how much ftronger the (hock ; and it may be compre- 

 hended, in general, to what point it mud be weakened in all 

 cafes where a greater or fmaller number of thefe forces a£l 

 contrary to each other by an inverted pofition of metals. 



If the chain be in any part interrupted, either by one of 

 the tumblers being empty of watej, or one of the metallic 

 arcs being removed or divided into two pieces, you will re- 

 ceive no fliock when you immerfe your finger into the water 

 of the firft and another into that of the laft veflel ; but you 

 will have it ftrong or weak, according to circumftances 

 (leaving thefe fingers immerfed), at the moment when the 

 interrupted communication is reftored ; at the moment when 

 another perfon fliall immerfe into the two tumblers, where 

 the arc is wanting, two of his^ngers (which will alfo receive 

 a flight fhock), or rather, when he (hall immerfe the fame 

 arc which has been taken away, or any other; and in the 

 cafe ot the arc feparatcd into two pieces, at the moment when 

 thefe pieces are again brought into mutual contaft (in which 

 cafe the (hock will be ftronger than in any other); and, 

 laftly, in the cafe of the empty tumbler, at the moment when 

 water poured into it ihaW rife to the two metallic arms im-' 

 merfed in this cup which before were dry. 



When the chain of cups is of fufRcient length, and ca* 

 pable of giving a ftrong (hock, you will experience one> 

 though much weaker, even though you keep immerfed two 

 fingers, or the two hands, in one bafon of water of pretty 

 Targe fize, in which the firft and laft metallic arcs are made 

 to terminate : provided that cither of thefe hands thus im- 

 hierfed, or rather both of them, be kept refpcftively in con* 

 tadl, or nearly in contaft, with thefe arcs, you will, I fay, 

 experience a fliock at the moment when (the chain being 



interrupted 



